What would $4,895 buy In 1987? A Threshold S/500 A-A/B Stasis power
amp.

This amp features a 1000KVA toroidal power supply,
backed by 116,000 uF of
storage. The design of this optical bias amp is to have no global
negative feedback. It has a bipolar transistor output, and a generous area
of heat-sinks around the case. What you end up with is an 82-pound battleship,
with about as much firepower. Since the S/500 was introduced in 1984,
the audio community and media have given it nothing less than stellar reviews,
placing it among the most topnotch "A" list equipment. This is deservedly
so.
I purchased my S/500 in used/mint condition in 1999
for a paltry $1,300 . I felt like I stole my way into the high-end.
I have heard a number of new power amps costing upwards of 9 kilo-bucks
that I didn't like better. That says a lot about the original design
genius of a 13 year old amp! This old amp extracted every bit of
detail off a source. It reproduced music in a neutral, grain-free,
non-fatiguing manner. I used material like Linda Ronstats "For sentimental
reasons" for vocals. The midrange was a liquid, transparent presentation,
which unlike many SS designs didn't sound flat, sterile, brittle,
grainy, opaque, or cold.
On classical material like "Mars, Bringer of war"
and "Hut on Fowl's legs" the bass proved to be the tightest, deepest, most
unblinkingly powerful I could hope to extract from a sound system.
The very deepest notes had incredible control and definition. During
a net search for Threshold information, I found Jon Soderberg's website.
He offered repair and upgrade to Threshold/Forte products. I thought,
if nothing else, maybe I could get the chassis freshened up on the inside,
- 13 years can be a long time for some internal components. What
does $425 buy in the year 2000? As far as amp mods go, a functional
bargain-basement tweak that really works well. I dropped my amp off
on a Monday, and picked it up on Saturday. The modifications included
upgrading the four 29,000uF/80v storage caps to 37,000uF/100v caps . The
power reservoir was now kicked up to 148,000 uF . The bias was adjusted
for modification to the front end circuit, and the aged power switch was
replaced for good measure.
Almost immediately, the effects of this modification
were obvious. No need for extensive DBT here. The same source material
was now more forward. By that, I do NOT mean "bright." I mean that the
air around instruments increased, and the soundstage was markedly improved.
It's like you went from row "E" to row "C." The conveyed sense of room
dimension was now more defined, and fine details became more prominent.
Michael Bromek's "Celtic Guitar", track 2 - "Second two O Carolan's pieces"
simply bloomed. The strings expanded outward magnificently, and when
he taps his hollow-bodied guitar, the sound of flesh on wood is very realistic.
Horns on "The best of Maynard Ferguson" and "The best of Chuck Mangione"
from the stock amp were fluid, but now it feels like you could step BEHIND
the horns. You sense the heat from staccato horn hits. The bass test came
via Telarc's "Space spectacular" the main theme to "Battlestar Galactica
" , "Star Trek TMP " and "Superman the movie." The bass impact was there
as before, but now with an edge. It's like the information was more finely
separated and etched. The visceral slam was improved. Zaranthrustra REALLY
spake…loudly.
I've seen companies offering questionable amp upgrades
that are also very expensive. They are nothing more than replacing all
the guts of an amp for the price of a new one. By contrast, this is a cost-effective
deal-and-a-half. I highly recommend this upgrade to any owner of a Threshold
product. It merely makes the already excellent amp more of what it already
is. It is like a product evolution. Nelson Pass has over-designed superb
products for years. Threshold provides the tube community with a solid
state alternative for detailed musicality without fatigue. For those of
you looking for a means of increasing personal enjoyment of a Threshold
amp, this upgrade will not disappoint!
Scott A. Lowell